Metronome



Aug. 4, 1925.

M. c. PAPPAS METRONOME Filed June 2, 1922 Patented Aug. 4, 1925.

UNITED STATESd MILTIADE C. PAPPAS, OE CI-IRISTIANIA, NORWAY.

METRONOME.

Application filed June 2, 1922.

7 To all whom it may concern:

Be it known that I, MILTIADE CONSTANTIN Parras, a subject of the King of Greece, re siding at Christiania, Norway, have invented new and useful Improvements Relating to Metronomes, of which the following is a specification.

The present invention relates to metronomes used in the teaching of music, and is based on the use as a metronome of a differential pendulum, said invention being mainly characterized by the fact that such pendulum does not rock about an axis, but rolls on a hard flat surface. According to the present invention, the metronome consists of a vertical pendulum of which the base is formed by a heavy mass suitably proportioned and provided with rolling surfaces having the shape of a curve resulting from a cycloid, the vertical rod of said pendulum being as usual provided with an adjustable weight so that the pendulum, when it is placed on a hard, polished flat surface, gives regular oscillations of which the value or amplitude depends on the position of the weight on the vertical rod.

Such an instrument is easily transportable, is of simple construction, and takes a smaller amount of room than the known types of metronomes. It is also more accurate.

In order that the invention may be easily understood, an embodiment thereof is, by way of example only, illustrated by the accompanying drawing wherein:

Fig. 1 is a perspective view of a metroname according to the invention, in position on its case and ready for use.

Figs. 2 and 3 are diagrams showing the method of determining the shape of the rolling surfaces of the base of the pendulum.

The differential cycloidal pendulum constituting the metronome according to the invention comprises as usual a vertical rod 1 carrying an adjustable weight 2-. The base of the pendulum is formed by a heavy mass having the shape of a sector of a disc 3, weighted as shown at 5, and provided with rolling surfaces 4 having the shape of a surface generated by a cycloid. As illustrated more particularly in Fig. 2 (wherein the line 7 9 represents the hard surface on which aforesaid rolling surfaces rock) the said. curve is the curve a 7) c symmetric to the cycloid A 7) B, the segment of circumference (Z 7) 6 being taken as axis of sym- Serial No. 565,497.

metry to describe the curve a 7) c relatively to the curve A 7) B.

The manner of obtaining the cycloid A 7 B from which the curved surface a 7) c is derived is illustrated. more particularly in Fig.

Referring to the said figure, the cycloid 7) B (being one of the identical halves of A. 7) has for directrix the cycloid O o: (5 Y 8, which is obtained. according to the following data:

The distance 6 O, onthe vertical crossing the flat surface f g perpendicularly at the point 7), is equal to 2X diameter bO.

The points I, II, III, IV on the horizontal passing through 0 are obtained from the formula:

distance 0 IV= X diameter 7) 0,

and so on.

The points a, (5, y, 8, through which the aforesaid directrix is drawn on the horizontals passing through the points x, y, a and 7) on the circumference of the circle having 7)'() as its diameter, are obtained by deducting respectively the distance 7t 72 from the distance 0 I, the distance a i from the distance O H, the distance 7' j from the distance 0 III, and the distance 7) 7):() from. the distance 0 IV.

To obtain the curve 7) c (being one of the identical halves of the curve a 7) c of the surface of the base of the pendulum) generated by the cycloid A 7) B by taking the arc of a circle (7 7) 0 described from Oas a centre with O 7) for radius as axis of symmetry to describe the said curve a 7) 0 in relation to the said cycloid A 7) B, it is sufficient to draw tangents to the directriX O 0:, (5, y, 8, at the points a (5 y and 6 and to place on the said tangents outside the arc o 6 points a", 'u", w", c, at distances from the points a, '0, w, e, where these tangents cross the are 7) (2 equal respectively to the distances between the said points a, o, w, e, and the points a, '0', w. B, situated inside said are 7), e, where the corresponding tangents cross the cycloid 7) B. The points a, 2), 4,1) and B, on the one hand. and the points a", o", w" and 0 respectively on the other hand, being equidistant in relation to the are 7) e, the curve a 7) c is symmetric to the cycloid A 7) B in relation to the segment of circle 67 b e taken as an axis of symmetry, and constitutes the immw M. C. PAPZUM.

GSSPS I 

